A Triggerable Declarative Object (TDO) (also sometimes known as a “Triggered Downloadable Object) is a downloadable object created by a content creator or service provider, which includes declarative content (text, graphics, scripts, and audio) whose function and behavior is tied in some way to digital television programming that it accompanies. Standards defining TDOs may be devised to specify associated available behaviors, appearance, trigger actions, and transport methods for content and metadata.